1. Field of the Invention
The present invention relates to a recording apparatus for recording by discharging a liquid such as ink and, more particularly, to a recording apparatus in which a liquid is supplied from a tank fixed to a recording apparatus main body having a recording head for discharging the liquid and the unused liquid is returned from the recording head to the tank.
2. Description of the Related Art
A recording head which is mounted in an ink jet recording apparatus records an image onto a recording medium such as paper by discharging minute ink droplets from minute discharge ports. In particular, a recording apparatus of a full line type using a line type recording head in which a number of discharge ports are arranged in the sheet width direction can realize a higher recording speed.
FIG. 14 illustrates an ink jet recording apparatus disclosed in Japanese Patent Application Laid-Open No. H09-104120. In FIG. 14, an ink jet head 1011 has a common liquid chamber 1012 and nozzles 1020. A supply tube 1017 as a flow path of supply ink to the common liquid chamber and a collecting tube 1016 as a flow path of collection ink from the common liquid chamber are respectively connected to both end portions of the common liquid chamber 1012 of the ink jet head 1011. The supply tube 1017 and the collecting tube 1016 are also connected to an ink ejecting portion 1013a and an ink inflow portion 1013b of an ink circulating pump 1013, respectively. The supply tube 1017 is constructed by: a three-directional joint 1017c; a tube 1017a on the common liquid chamber side of, and connected to, the joint 1017c; and a tube 1017b on the ink circulating pump side of the joint 1017c. 
In an ink supply pump 1014, an ink inflow portion 1014a is connected to a main ink tank 1015 by a tube 1019 and an ink ejecting portion 1014b is connected through an inflow tube 1018 to the 3-directional joint 1017c provided halfway along the supply tube 1017.
There has been disclosed such a technique that at the time of the recovery operation by the ink circulation, the ink circulating pump 1013 and the ink supply pump 1014 are made operative and, in each of the pump portions, the ink is moved in the direction shown by an arrows A in the diagram.
According to the construction disclosed in Japanese Patent Application Laid-Open No. H09-104120, when the ink is initially filled into the ink jet head 1011, the ink is filled with a pressure from both sides of the common liquid chamber 1012 by the ink circulating pump 1013 (pumping the opposite way) and the ink supply pump 1014. At this time, while the ink is filled toward a center portion in the common liquid chamber 1012, the air in the common liquid chamber 1012 is ejected to the atmosphere from the nozzles 1020. However, there is such a problem that the air near the center portion in the common liquid chamber 1012 cannot be completely exhausted.
Therefore, according to the construction disclosed in Japanese Patent Application Laid-Open No. H09-104120, the ink circulating pump 1013 and the ink supply pump 1014 are made normally operative and the ink in the common liquid chamber 1012 is circulated, as mentioned above, thereby exhausting the air in the common liquid chamber 1012. At this time, the ink in the common liquid chamber 1012 is ejected from the nozzles 1020 together with the air.
In particular, in the recording apparatus of the full line type using the line type recording head in which a number of discharge ports are arranged in the sheet width direction, there is such a problem that a large quantity of drain ink occurs. The sheet width direction is typically the direction perpendicular to the direction of travel of the sheet, and so parallel to the longitudinal axis of the line of discharge ports.
If a pressure or a rotational speed of the ink circulating pump 1013 or the ink supply pump 1014 is decreased in order to reduce the amount of drain ink at the time of the initial filling of the ink, the filling time becomes long.